Incandescent lamp with means to reduce bulb blackening



March 21, 1939. A, NUTTO 2,151,522

INCANDESCENT LAMP WITH MEANS TO REDUCE BULB BLACKENING Filed Sept. 22, 1957 J: 1 INVENTOR wmpum ATTO R N EY Patented Mar. 21, 1939 INCANDESCENT LAMP WITH MEANS TO REDUCE BULB BLACKENING Louis A. Nutto, North Arlington, N. J., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation 01' Pennsylvania Application September 22, 1937,Serial No. 165,052

14 Claims. (Cl. 176- 16) This invention relates to incandescent electric lamps and more particularly to such of the gasfilled typehaving means toreduce bulb blacken- The principal object of my invention generally considered is the provision of an electric lamp having means, such as metal plates, mounted therein, to reduce the vaporization of filament material and collect such material that does evaporate, in order to reduce bulb blackening.

Another object of my invention is the employment of metal plates in an incandescent electric lamp for collecting the metal evaporated from the filament in order to reduce bulb blackening.

A further object of my invention is the provision of a gas-filled lamp, particularly adapted for projection purposes. and containing two plates held in position by attachment to a spud or spuds in the bridge from which the filament is suspended, the dimensions of said plates being determined by the size of the light source and the bulb dimensions, said plates being desirably mounted at an angle to one another and disposed so as to normally be above and on either side of the filament.

Other objects and advantages of the invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing illustrating my in vention:

Fig. l is a side elevational view of a projection lamp embodying my invention, with portions of the envelope or bulb broken away to more clearly show the interior construction. Fig. 2 is a partial vertical elevation, looking in a direction at right angles to that of Fig. 1, with portions of the envelope broken away to more clearly show the interior construction.

Fig. 3 is a detail perspective view of the blackening-reducing plates and supporting wire.

Fig. 4 is a view similar to Fig. 3, but showing a modification.

In ordinary practice the metal evaporated from the incadescent filament in a lamp is deposited on the bulb wall, causing an appreciable loss in lumen output due to absorption of light by the deposited material. This-light absorption also increases the bulb temperature in some cases to such an extent that the glass softens and becomes distorted or blows 'out, due to the difference between atmospheric pressure and the pressure inside the lamp..

To diminish the amount of material deposited on the bulb, and consequently to improve the lumen maintenance and reduce the bulb temperature, I propose the use of means such as metal plates for collecting evaporated material, and also reducing the amount of material actually evaporated, as will now be described in detail.

Referring to the drawing, like parts being designated by like reference characters and first considering the embodiment of my invention illustrated in Figs. 1, 2, 3, there is shown a lamp Ill comprising an envelope or bulb I! with a base indicated at I2, enclosing a mount 13.

The mount of the present embodiment com prises a flare tube l4 sealed to the bulb and pro vided with an exhaust tube, not shown, and an arbor or button l5- extending from the press I6. Leading-in conductors l1 and I8 extend through the press from the base l2 and connect with relatively rigid inner supporting leads l9 and 20, which may be formed of nickel or other suitable material, with their normally lower ends embedded in the press IB. In the present embodiment the normally up per or free ends of the supporting leads I9 and are connected by wires 2| and 22,.the outer ends of which are spot-welded thereto as indicated at 23 and 24, and the inner ends of which are embedded in an insulating member or bridge 25, which may be a piece of glass cane.

Depending from the insulator 25 are a plurality of supporting members 26, 21, 28, 29, and 30, the number depending on how many coiled sections the filament 3| is formed with. In the present embodiment, the coiled filament 3| comprises eight coiled sections which are connected by intersection loops and staggered, so that four are disposed in one normally vertical plane and four in a normally vertical plane parallel thereto, and so spaced that in plan they lie at the vertices or isosceles triangles.

The upper uncoiled portions of the connected sections of filament 3| are draped over the hooked or doubled-over lower ends of members 26 to 30 inclusive, as illustrated, and the extreme coiled end sections 32 and 33 forced over connecting members 34 and 35, the outer ends of which are desirably spot-welded to the supporting leads I9 and 20 respectively. Outer coils 36 and 31 may be screwed over the coiled end portions 32 and 33 for shortecircuiting the turns thereof to improve the uniformity of rating.

The order to hold the filament 3| in position between the leads l9 and 20, and at the same time avoid strains due' to expansion and contraction of the metal parts in the lamp, I provide a light bridge assembly 38, which desirably comprises an insulating portion 89, preferably formed of a piece of glass cane, and end wires 44 and 4i, the inner ends of which are embedded in the insulator II and the outer ends of which normally extend diagonally outward and upward and are formed with eyes or loops 42 and 43 to receive the supporting leads I! and 20 respectively. The .eyes or loops 42 and 43 are desirably adjusted so as to slide freely on the leads I! and 28 with the avoidance of binding, even when the bridge device 38 is slightly tilted with respect to said leads.

The bridge device 3! is normally suspended from the filament 3| by having members 44, 45, 4., and 41, the lower ends of which are embedded in the insulator 39 and the upper ends of which are bent to hook over the loops formed between the lower portions of the coiled sections of filament ii.

In order to prevent undesired tilting of the bridge device 34, when the lamp is inclined from its normally vertical base-down position, the insulator 39 is desirably provided with a bottom guide 4| slidably' cooperating with a wire 49 extending upwardly from the arbor l5.

Inasmuch as the lamp illustrated is of the type in which the filament is operated at a very high temperature to give a great amount of light with a relatively short life, said filament is desirably surrounded by an 'inert gas to reduce vaporization therefrom. In spite of this, vaporization takes place, and I have found that if metal plate means is disposed adjacent the filament in the bulb, such means tends not only to collect the evaporated metal, but to suppress vaporization.

In the present embodiment, the plate means employed comprises a pair of desirably imperiorate plates 50 and ii, formed of metal such as nickel or molybdenum, which plates are desirably mounted so as to normally extend above and lie on either side of the filament, as shown most.

clearly in Figs. 1 and 2. For that purpose, the plates 50 and ii are secured to the ends of a wire 52, as by spot-welding, which wire is looped over the insulating bridge member 25 and supported therefrom, as by being spot-welded to a spud 53 extending upwardly from the approximate mid-portion thereof. In order to improve the connection between the wire 52 and the spud 53, the curved upper portion of the said wire desirably has first applied thereto a metallic fiux which may consist of a coil 54 of relatively fine wire.

As illustrated, the plates 54 and ii are desirably disposed so that their lower edges are slightly above the upper ends of the coil 3|, said plates being desirably inclined with respect to one another so that the included angle is from about 20 to 30 degrees. As illustrated, the lower edges of the plates may be separated about 16 millimeters, and the top edges about 8 millimeters, although the size of the plates, and the spacing thereof, desirably varies in accordance with the size of the light source and the enclosing bulb. The wire is desirably extended between its curved portion and where it is connected to the plates 54 and SI, so that the plates are properly positioned with respect to the filament.

Referring now to the embodiment of my invention illustrated in Fig. 4, a construction is there disclosed in which plates 50' and SI are, as in the preceding embodiment, connected by a supporting wire 52' having a coil 54' encircling the curved intermediate portion, which is connected to a supporting spud, like that designated 53 in Figs. 1 and 2. The plate construction may correspond approximately with that of the preceding embodiment, except that each plate has its side edges flanged inwardly, as indicated at 55, 58, 51 and ll, so as to close up some of the space left between said edges and thereby improve the collecting characteristics of the plates.

From the foregoing disclosure it will be seen that I have devised an incandescent lamp in which means are provided for reducing the amount of metal vaporized during operation, and also for collecting the metal which does vaporize, and preventing, to a large extent, its deposit on the bulb, thereby improving the lumen maintenance throughout life.

Although preferred embodiments of my invention have been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.-

I claim:

1. An incandescent electric lamp comprising an envelope, a base, interior supporting leads extending from said base in said envelope, a filament secured thereto, and imperforate metal plate means supported in the part of the envelope remote from the base and beyond said filament, for decreasing the amount of metal evaporated from the filament during operation.

2. An incandescent electric lamp comprising interior supporting leads, a metal filament associated therewith, and plate means supported by and insulated from such leads for collecting material evaporated from the filament and reducing the amount of such material deposited on the bulb.

3. An incandescent electric lamp comprising supporting leads, a refractory metal filament associated therewith, plate means supported by said leads for collecting material evaporated from said filament, and common insulating means connecting said leads and supporting said filament and plate means.

4. An incandescent electric lamp comprising interior supporting leads extending from a press, the free ends of said leads being connected by an insulator member, a refractory metal filament comprising a plurality of coiled sections supported from said insulator member, and a plate also supported by said member and serving to collect material evaporated from said filament during operation.

5. An incandescent electric lamp comprising -interior supporting leads, a coiled filament disposed therebetween, an insulator, the ends of which are connected to the free ends of said supporting leads, means depending from said insulator for supporting said filament, a spud extending upwardly from said insulator, and a pair of plates secured to said spud by a wire extend- I ing over said insulator.

6. An incandescent electric lamp comprising interior supporting leads, a coiled filament disposed therebetween, an insulator, the ends of which are connected to the free ends of said supporting leads, means depending from said insulator for supporting said filament, a spud extending upwardly from said insulator, and a pair of plates secured to said spud by a wire extending over said insulator, the lateral edges of said plates being flanged inwardly toward one another.

7. An incandescent electric lamp comprising supporting leads, a filament disposed therebetween, and a pair of metal plates angularly disposed with respect to one another and overlying said filament for collecting material evaporated therefrom during operation.

8. An incandescent electric lamp comprising interior supporting leads, a coiled filament disposed therebetween, an insulator, the ends of which are connected to the free ends of said leads, means depending from said insulator for supporting said filament, and a pair of plates supported by said insulator, overlying said filamerit, and angularly disposed with respect to one another.

9. An incandescent electric lamp comprising a bulb, a refractory metal filament supported therein, and plate means overlying said filament for collecting material vaporized therefrom, said means having the outer edges Iormed with tapering flanges.

10. An incandescent electric lamp comprising a press, interior supporting leads extending therefrom, an insulator member connecting the free end portions of said leads, a refractory metal filament supported from said insulator member. and a plate also supported by said member and serving to collect material evaporated from said filment during operation.

11. An incandescent electric lamp comprising interior supporting leads, a coiled filament, an insulator, the ends of which are connected to the free ends of said supporting leads, a spud extending upwardly from said insulator, and a pair of plates secured to said spud by a wire extending over said insulator.

12. An incandescent electric lamp comprising interior supporting leads, a coiled filament, an insulator, the ends of which are connected to the free ends of said supporting leads, a spud extending upwardly from said insulator, and a pair of plates secured to said spud by a wire extending over said insulator, the lateral edges of said plates being flanged inwardly toward one another.

13. An incandescent electric lamp comprising interior supporting leads, a coiled filament, an insulator, the ends of which are connected to the free ends of said leads, and a pair of plates supported by said insulator, overlying said filament, and angularly disposed with respect to one another.

14. An incandescent electric lamp comprising a bulb, a metal filament supported therein, and plate means for collecting material vaporized therefrom, said means having the outer edges formed with flanges.

LOUIS A. mo. '5 

